Updated variant of Zoom to Bounding Box II for d3 v4 which is also a variant of the Zoom to Bounding Box example that uses zoom transitions to smoothly interpolate between different views. This example also allows you to freely pan and zoom with the mouse (or touch).
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Zoom to Bounding Box II - Updated for d3 v4
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| license: gpl-3.0 |
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| .background { | |
| fill: none; | |
| pointer-events: all; | |
| } | |
| .feature { | |
| fill: #ccc; | |
| cursor: pointer; | |
| } | |
| .feature.active { | |
| fill: orange; | |
| } | |
| .mesh { | |
| fill: none; | |
| stroke: #fff; | |
| stroke-linecap: round; | |
| stroke-linejoin: round; | |
| } | |
| </style> | |
| <body> | |
| <script src="https://d3js.org/d3.v4.min.js"></script> <!-- Inclusion of d3 v4 --> | |
| <script src="https://d3js.org/topojson.v1.min.js"></script> | |
| <script> | |
| var width = 960, | |
| height = 500, | |
| active = d3.select(null); | |
| var projection = d3.geoAlbersUsa() // updated for d3 v4 | |
| .scale(1000) | |
| .translate([width / 2, height / 2]); | |
| var zoom = d3.zoom() | |
| // no longer in d3 v4 - zoom initialises with zoomIdentity, so it's already at origin | |
| // .translate([0, 0]) | |
| // .scale(1) | |
| .scaleExtent([1, 8]) | |
| .on("zoom", zoomed); | |
| var path = d3.geoPath() // updated for d3 v4 | |
| .projection(projection); | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width) | |
| .attr("height", height) | |
| .on("click", stopped, true); | |
| svg.append("rect") | |
| .attr("class", "background") | |
| .attr("width", width) | |
| .attr("height", height) | |
| .on("click", reset); | |
| var g = svg.append("g"); | |
| svg | |
| .call(zoom); // delete this line to disable free zooming | |
| // .call(zoom.event); // not in d3 v4 | |
| d3.json("/mbostock/raw/4090846/us.json", function(error, us) { | |
| if (error) throw error; | |
| g.selectAll("path") | |
| .data(topojson.feature(us, us.objects.states).features) | |
| .enter().append("path") | |
| .attr("d", path) | |
| .attr("class", "feature") | |
| .on("click", clicked); | |
| g.append("path") | |
| .datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; })) | |
| .attr("class", "mesh") | |
| .attr("d", path); | |
| }); | |
| function clicked(d) { | |
| if (active.node() === this) return reset(); | |
| active.classed("active", false); | |
| active = d3.select(this).classed("active", true); | |
| var bounds = path.bounds(d), | |
| dx = bounds[1][0] - bounds[0][0], | |
| dy = bounds[1][1] - bounds[0][1], | |
| x = (bounds[0][0] + bounds[1][0]) / 2, | |
| y = (bounds[0][1] + bounds[1][1]) / 2, | |
| scale = Math.max(1, Math.min(8, 0.9 / Math.max(dx / width, dy / height))), | |
| translate = [width / 2 - scale * x, height / 2 - scale * y]; | |
| svg.transition() | |
| .duration(750) | |
| // .call(zoom.translate(translate).scale(scale).event); // not in d3 v4 | |
| .call( zoom.transform, d3.zoomIdentity.translate(translate[0],translate[1]).scale(scale) ); // updated for d3 v4 | |
| } | |
| function reset() { | |
| active.classed("active", false); | |
| active = d3.select(null); | |
| svg.transition() | |
| .duration(750) | |
| // .call( zoom.transform, d3.zoomIdentity.translate(0, 0).scale(1) ); // not in d3 v4 | |
| .call( zoom.transform, d3.zoomIdentity ); // updated for d3 v4 | |
| } | |
| function zoomed() { | |
| g.style("stroke-width", 1.5 / d3.event.transform.k + "px"); | |
| // g.attr("transform", "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")"); // not in d3 v4 | |
| g.attr("transform", d3.event.transform); // updated for d3 v4 | |
| } | |
| // If the drag behavior prevents the default click, | |
| // also stop propagation so we don’t click-to-zoom. | |
| function stopped() { | |
| if (d3.event.defaultPrevented) d3.event.stopPropagation(); | |
| } | |
| </script> |
Thanks for this really helpful. This example is using GEOJSON, what edits should be made to load in TopoJSON?. Also it maybe worth commenting this in somewhere. Im new to this and struggling to work out when people are using GEO and TOPO.
Thanks
Just wanted to say thank you for sharing this. The majority of examples out there for this type of functionality are in v3, and it's not easily translatable. This just flat out works, and I appreciate the comments showing what changed between v3 and v4.
👍
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Thanks for sharing!